Desires & Aspirations.

Aum Sai Ram.

A Mango tree is a full fledged Mango tree, a Dog is a full fledged Dog. So they have no "Desires" to be anything else.

ONLY humans aspire to be like someone else [a lot of us have role models and stuff] because they feel themselves [more likely have been made to feel] to be less than complete.

The whole rigamarole for humans, therefore, is to feel complete WITH ALL kinds of accessories.

It takes a whole life time [sometimes even that does not seem to suffice) to understand / know, that we have been created complete.

That ALL has been and IS being taken care of.